Add leaves reset, split holidays/leave resets, support multi-table reset

backend/main.py

@@ -1936,19 +1936,25 @@ async def reset_section(
     db: Session = Depends(get_db),
 ):
     """Reset (truncate) a specific data section. Creates auto-backup first."""
-    valid = {"attendance": AttendanceRecord, "holidays": Holiday, "leaves": LeaveRecord, "accident": Accident}
-    if section not in valid:
+    single_models = {"attendance": AttendanceRecord, "accident": Accident}
+    if section not in single_models and section not in ("holidays", "leaves"):
         raise HTTPException(status_code=400, detail=f"Unknown section: {section}")
     # Auto-backup before reset
     src = Path(DB_PATH)
+    auto_dst = None
     if src.exists():
         auto_dst = _backup_path(f"auto_pre_{section}_reset")
         shutil.copy2(src, auto_dst)
-    # Truncate table
-    model = valid[section]
-    db.execute(model.__table__.delete())
+    # Truncate table(s)
+    if section == "holidays":
+        db.execute(Holiday.__table__.delete())
+        db.execute(LeaveRecord.__table__.delete())
+    elif section == "leaves":
+        db.execute(LeaveRecord.__table__.delete())
+    else:
+        db.execute(single_models[section].__table__.delete())
     db.commit()
-    return {"reset": section, "auto_backup": auto_dst.name}
+    return {"reset": section, "auto_backup": auto_dst.name if auto_dst else None}
 
 
 @app.get("/api/version")